Thermal cut-out device



(No Model.)

2 Sheets-Sheet l. C. A. ROLE1 THERMAL GUT-OUT D GE.

No. 538,284. Patented Apr. 30, 1895.

' 2 sheets-sheen 2. C. A. ROLPE.

THERMAL GUT-OUT DEVICE.

Patented Apr. 30, 1895.

UNITED STATES PATENT OFFICE.

CHARLES A. ROLFE, OF CHICAGO, ILLINOIS.

THERMAL CUT-OUT DEVICE.

SI]31(`J'I'.I1"I[('JATION forming part of Letters Patent No. 538,284., dated April 30, 1895,

[Application led February 21, 1895. Serial No. 539,166. (No model.)

- To aZZ whom may concern.-

Be it known that I, CHARLES A. RoLFE, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a. certain new and useful Improvement in Thermal Cut-Out Devices, of which the following is a specification.

My invention relates to thermal cut-out devices in which the circuit is broken as the result of the fusion of a body of fusible material induced by the development of heat in a conductor of high resistance, and is particularly designed as an improvement upon the thermal cut-out described in Letters Patent of the United States No. 445,217. The thermal cutout or thermal protector for an electric circuit and apparatus therein, as embodied in said patent, contemplates the employment of a mass of material solid and hard at a normal temperature, but adapted to fuse or soften when heated, and a loop or hook, and a wire of high resistance, both embedded in said fusible mass, and a spring engaging the loop or hook and held under tension, so that when the wire which :is included in the circuit becomes heated by reason of an unduly strong current, the fusion or softening of the mass of fusible material will permit the spring to tear the hook or loop therefrom and operate to break the wire.

My improvement contemplates the bodily removal of the high resistance wire from the circuit, as a result of the fusion or softening of a mass of material such as set forth in said patent, and to such end I provide in connection with a movable holder for the terminals of the high resistance wire, and a suitably held mass of fusible material, a spring which is normally held under tension and which is tripped or released by the fusion or softening of said mass, the result of thus releasing the spring being that it will operate to cause the bodily removal of the high resistance wire from the circuit, and as herein set forth, I may employ such spring either with or without the spring described in said patent. v

In the accompanying drawings, Figure 1 represents in elevation a thermal cut-out embodying my invention. Fig. 2 shows the hook or loop and a portion of the high resistance wire wrapped about the same, the mass of plastic material in which the hook or loop and coil are embedded being indicated in outline by dotted lines. Fig. 3 is a vertical section through Fig. 1 on line roalookingin the direction of the arrow. Fig. 4 is asection on line 'y y, Fig. l. Fig. 5 is a top plan view. Fig. 6 shows on a larger scale the removable portion of the device separated from the portion which is secured upon the base K. Fig. 7 shows the device on a reduced scale, with the spring I of preceding figures omitted. Fig. 8 is a like View, showing both the spring I and the catch B of certain preceding figures omitted, further illustrating the stop or holder for the fusible mass or button arranged upon the base K.

In the first six gures of the drawings, the thermal cut-out (with the exception of spring A and a catch B for temporarily holding said spring under tension) involves the general construction and arrangement of the thermal cut-out described in Letters Patent of the United States,No. 445,217. Said construction and arrangement may be briey referred to, as followsz-The plate C of non-conducting material is provided with metal end pieces c which are held within and in contact with spring metal jaws D. A fine wire E of high resistance bridges the space between the metal end pieces c on the non-conducting plate, and is wrapped upon the shank of a hook or loop F, which is then embedded in a mass G, of easily fusible substance or material which easily softens or becomes friable when subject to a moderate degree of heat. The stein portion of this fusible button extends through an eye II on the non-conducting plate C, said eye being arranged to support the mass G (which for convenience may hereinafter be termed a fusible button), and to further provide a stop against which the head or larger portion of the button is normally held by the tension of a spring I secured upon the nonconducting plate C and having one of its arms i in engagement with the hoop or loop F. The metal jaws D, the metal plates o held by said jaws, and the wire E, are all included in the circuit. When therefore an unduly strong current comes in the circuit, the heat developed in the fine wire will fuse the button and IOO thereby liberate the hook or loop to which said wire is attached, and thereupon the spring arm engaging the hoop or loop will move in a direction to cause a sudden strain upon and a consequent rupture in the tine wire, and thereby break the circuit.

Vith reference to the application of myimprovement to a thermal cut-out of the foregoing described construction, I arrange a spring A upon the base K, and provide such spring with an arm a, which when free will extend upwardly or away from the base of the device, as illustrated by dotted lines. The spring is however, normally under tension, and to such end its arm a is held down by a catch B and arranged to extend under the non-conducting plate C. rIhis plate C is removably held in circuit by the jaws D, and hence, when the spring arm is released from catch B, it will liy up, and in so doing will en gage the plate C and throw the same out of engagement with the jaws, and thereby break the circuit. The spring A is released from catch B, primarily by the meeting orsoftening of the fusible button, and to such end, the arm of spring A is held by catch B, in position adjacent to the arm of spring I and in the path traversed by said arm when the hook or loop F is released. When therefore the hook or loop F is thus released, the arm t' of spring I will strike and throw the arma of spring A out of engagement with catch B, and thereupon, the spring arm will spring upwardly and kick the plate C which carries the wire E,out of thespring jaws andthereby break the circuit. Should the action ofspring I fail to break the fine wire carried by the non-conducting plate C, the fault will be remedied by the kicker-spring A (as I may term it) which will kick the support forthe resistance wire E out of circuit. In this way, two modes of breaking the circuit can be relied upon, and hence, should one fail, theother will do the work.

From the foregoing it will be seen that the fine wire of high resistance is normally in the circuit and is connected with a spring which is normally held; under tension by a fusible mass or button, and further, that when the spring is released by the fusion or softening of said mass or button, it operates in a direction tending to break the fine wire,

and at the same time release the kicker I, a weight, could be employed as set forth in said patent, it being obvious that the drop of the weight could be caused to trip the kicker-spring.

I may also dispense with the spring I which` trips the kicker-spring, and in lieu of such spring tripping device, I can connect the kicker-spring with the fusible mass or buthook or loop, and to such end the arm of the kicker spring can be depressed and also deflected laterally so as to bring it under a catch B (Fig. 7) and permit it to engage the hook or loop F. With such arrangement, the eye or stop which supports and holds the fusible button can be arranged upon the nonconducting plate() as in Fig. 6, and preceding figures. l/Vhen therefore the fusible button is melted or softened to an extent to cause it to release the hook or loop, the spring arm a will move out of engagement with the catch and also operate to kick the plate or support C free from the spring jaws and thereby break the circuit. As another arrangement, the eye or stop which holds the fusible button can be arranged upon the base K as in Fig. 8, and in such case the catch for the arm of the kicker spring need not be employed, since the spring arm will be normally held down by the loop or hook embedded in the fusible button. lVhen the fusible button thus arranged becomes suiliciently fused or softened to allow thc springarm to tear away the hoop or loop, the said spring arm will fly upand kick the holder for the fineV wire out of circuit.

From the foregoing it will be seen that each of the several arrangements involves a mass or body of fusible material, a section of circuit conductor removably held in circuit and comprising a wire of high resistance in part coiled within the fusible mass, and a holder for the wire having contact portions with which the said wire is connected, and a spring `normally held under tension by the fusible `mass and arranged to throw the section of circuit conductor out of circuit when said spring is released by the fusion or softening of the fusible mass; also that a weight could be. substituted for the spring.

What I claim as my invention isl. The combination in a thermal cut-out, of a body of fusible material, a section of circuit conductor removably held in circuit and comprising a wire of high resistance in part coiled within the fusible mass and a holder for the wire having contacts with which the wire is connected, and a spring or weight normally held in tension by the fusible mass and arranged to throw the movable section of circuit conductor awayfrom its cooperating contacts and out of circuit when it is released bythe fusion or softening of the mass of fusible material, substantially as described.

2. The combination in athermal cut-out, of a body of fusible material, a section of circuit conductor removably held in circuit and comprising a Wire of high resistance in part coiled within the fusible mass and a holder for the wire having contacts with which the wire is connected, a spring normally held in tension by the fusible mass, and a kicker spring normally held in tension by a catch, the spring normally held in tension by the fusible mass being arranged to free thekicker spring from the catch when it is liberated by which is normally held by the fusible mass, the fusion or softening of the fusible mass, substantially as described. and the kicker spring being arranged to i throw the removable section of circuit eon- CHARLES A' ROLFE 5 duotor away from its (3o-operating contacts Witnesses:

and out of circuit when it is thus released ARTHUR F. DURAND, from the catch by the action of the spring RETA M. WAGNER. 

